Science Reviewer

1 | P a g e M a r i e J a j a T . R o a
Science Grade 4 Reviewer
QUARTER 1: MATTER
1. Density is the degree of compactness of an object; density causes objects to float or sink
2. Sink- means to fall to the bottom of water, float- means to stay on top
 Objects with tightly packed molecules will sink if it is more dense than the liquid it is
immersed into.
 Objects with loosely packed molecules will float if it’s less dense than the liquid it is placed
in.
 Materials with a density less than that of a liquid float and materials with a greater density than
the liquid sink.
 Changing the object’s shape will make its ability to float because it holds air and upthrusts has
more space to push the object
 Upthrust is the force that pushes an object up and make it seem to lose weight in a liquid.
 Shape affects upthrust; the larger the surface area of an object, the stronger the upthrust.
 Explain why do ships and boat floats on water.
o Large ships and boats float on water because of upthrust; the upward push (upthrusts)
of the water is greater than their weights.
 Some things float at first, but then sink as they absorb water or take water on through holes
 Life vests keep us afloat in water because it makes us occupy a bigger space, increasing the
upward force of the water on us and making us float
3. Absorb- to take in (something, such as a liquid) in a natural or gradual way
4. Repels means to move away
5. Porous- having small holes that allow air or liquid to pass through; example cotton
6. Non- porous- materials that do not allow air or liquid to pass through; example plastic
7. Garbage or waste is the stuff we don't need anymore, the junk we think is useless.
 It's the rejects we don't want to deal with, and the cast-offs from the way we live. It comes from
our homes, businesses, government agencies, and institutions like schools and hospitals.
 Garbage is also known as "municipal solid waste." If not dispose of properly, it causes pollution
that is harmful to our environment and our health.
 Waste should never be disposed down sinks, drains, lavatories, ditches, near wildlife habitats
or ponds.
8. Biodegradable are materials that are able to degrade or breakdown into very small parts by
sunlight, water and organisms/decomposers (worms, insects, bacteria, fungi)
 Biodegradable materials can be recycled through composting; it undergoes decay and become
soil
9. Composting is “nature’s way of recycling”; it is a natural process of death, decay, and rebirth.
 Explain why composting is considered as “nature’s way of recycling.”
oComposting is nature’s way of recycling because composting biodegradable waste
such as fruit and vegetable peelings, paper and grass trimmings, decays and turns
into a valuable organic fertilizer into the soil.
10.Compost- waste materials that are recycled as a fertilizer
 Making compost is one way of disposing garbage properly
11.Decomposers are organisms that helps break down biodegradable waste; worms, insects,
bacteria, fungi
12.Decay- to be slowly destroyed into bits in the presence of water, air, and soil
 Plants and animals compressed under water and think layers of soil over millions of years
were converted into fossil fuels such as coal, oil or natural gas
 Why are left over food kept in a refrigerator?
o Leftover food are kept in refrigerators to avoid delay spoilage since microorganisms that
break down food do not grow fast in cold temperature.
13.Organic fertilizer are organic matter in soil derived from decayed plants and animals
 Organic fertilizer from compost pit does not harm but enrich the soil.
 Factors in decaying process of materials: sunlight, water, soil and action of microorganisms

14.Non- biodegradable are materials that cannot be broken down by organisms.
 Non- biodegradable garbage is not going to decay EVER or the decay will take thousands of
years.
 These items are usually made from chemicals or minerals that do not break down.
15.Total Recycling Scheme or multi-F’s Recycling Scheme- is zero- waste technology technique
which aims to use wastes to the fullest to maintain round-the-clock cleanliness, orderliness,
beauty and dignity.
 It is a technique or procedure use to utilize wastes into factory returnable, fertilizers, feeds,
fermentable, fuel, fine crafts and filling materials.
 The Multi- F’s Total Recycling Scheme follows three steps: (1) Sort at Source: Segregate bio-
degradable and non- biodegradable wastes in different bins; (2) Package Properly: Place
segregated wastes according to kind in proper containers, for example, when throwing sharp
objects you should placed it in a cardboard box, tape the box and mark it as trash; (3)
Use/Dispose “ecologically”: compose and recycle if possible.
16.Recycling is collecting, processing and manufacturing materials instead of throwing them away.
 It is the process by which materials can be turn into new materials instead of throwing them
away. Recycling lessen the amount of garbage we have to dispose.
17.5R’s (Reduce, Re- use, Recycle, Repair, Rot)
 Reduce to use less. Think about what you use and buy.
 Reuse something you already have instead of buying something
 Recycle all the basics you can
 Repair or fix stuff before tossing it and buying new
 Rot- compost biodegradable materials
18.Proper Waste Disposal must be done to avoid harming the environment that pollutes the land and
water.
 Separate/segregate materials into decaying (biodegradable) and non- decaying (non-
biodegradable)
 Use appropriate equipment or safety gears when disposing non- biodegradable
 Sharp objects should be placed in a cardboard box and close of tape the box and mark it as
trash
 Recycle biodegradable materials such as plastic and bottles
 What are the ways of disposing ways materials?---- Group them according to properties.
Separate biodegradable and non- biodegradable waste. Practice the Multi F’s Total Recycling
Scheme, compost the biodegradable waste to become fertilizers, feed leftover food to pets.
For non- biodegradable waste, recycle them as new materials and for factory returnable waste
such as broken electrical appliances, have them repair or sell it to junkshops.
 What are you going to do with the materials that undergo decay to make it useful?---Make a
compost make the soil fertile.
19.Pollution- action or process of making land, water, air dirty and not safe to use
20.Diseases- an illness that affects a person, animal, or plant; a condition that prevents the body or
mind from working normally
 How could people living in areas near dumpsites, esteros or canals be protected from
getting sick?
oProper disposal of waste should be observed in areas near dumpsites, esteros or
canals to prevent them from too much exposure to garbage that will result to danger.
oGood hygiene practices such as washing of hands, boiling of water.
21.Malaria is a life- threatening mosquito borne blood disease caused by a Plasmodium parasite
that is transmitted to humans through the bite of the Anopheles mosquito
22.Dengue is an acute infectious disease caused by flavivirus transmitted by Aedes mosquito.
23.Typhoid fever- is an acute illness caused by Salmonella typhi bacteria. The bacteria are
deposited in water or food by a human carrier and then spread to other people in the area.
24.Dysentery- is a waterborne disease that can cause severe diarrhea and leads to death when not
treated.

25.Product Labels- are intended to ensure the safety of the product user. They (1) give the product
ingredients (to which someone might be allergic), (2) they describe the safe way of using the
product, including the dose (in the case of medicine), and they (3) describe the proper way of
storing the product.
 Explain why people need to consider the information on product labels when buying
products to be stored at home.
oPeople need to consider the information on product labels when buying products to
be stored at home to be aware of how to use the product especially in the case of
medicine. Labels warn possible danger.
26.Matter is everything around you. Atoms and molecules are all composed of matter.
 Matter is defined as anything that has mass and takes up space.
 it is the amount of stuff in an object.
27.Matter (solid, liquid and gas) undergoes changes. It change physically when the property can be
observed without changing what a substance is made of.
 When a substance changes in appearance or state without changing its composition or
what it is made of, physical change occurs. Physical change does not involve a chemical
reaction. Therefore, no new material is formed. The original characteristics of the
substance remain the same.
28.Solid has definite shape and volume.
 Physical properties of solid materials can be changed through many ways: by cutting,
tearing, folding, twisting, bending, stretching, pressing, coloring, crumpling, and melting.
But no new material is formed, only the physical properties of the material changed.
Changes in the Physical Properties of Solid Materials
Size Shape Texture Color Weight New material
formed
Cutting YES YES NO NO NO NONE
Tearing YES YES NO NO NO NONE
Bending YES YES NO NO NO NONE

29.Thermometer is a tool or device that measures temperature.
30.Temperature is a measurement that indicates how hot or cold something is.
 Temperature affects the phase of matter by breaking the bonds between the molecules of a
substance, leading it to change its state.
 When a substance changes from one state, or phase, of matter to another we say that it
has undergone a change of state, or we say that it has undergone a change of phase. For
example, ice melts and becomes water; water evaporates and becomes water vapour,
water vapor condenses and becomes water, water freezes and becomes ice .
 These changes of phase always occur with a change of heat, leading to change in
temperature. Heat, which is energy, either comes into the material during a change of
phase or heat comes out of the material during this change.
 When we heat a solid, the energy supplied is used to increase the kinetic energy of its
molecules, and thereby its temperature increases. Energy is required to melt a solid,
because the cohesive forces between molecules must be partially overcome to allow the
molecules to move about. Similarly, energy is required to vaporize a liquid, because in so
doing the molecules are separated and molecular attractive forces are overcome.
 When freezing or condensing, it is totally opposite of heating. The heat is given of the
liquid, decreasing its temperature and the kinetic energy between the molecules.
 When a material changed its phase (solid to liquid or liquid to solid) it changed its size, shape
and texture.
Size Shape Texture Color Weight New material
formed
Crumpling YES YES YES NO NO NONE
Folding YES YES NO NO NO NONE
Stretching YES YES NO NO NO NONE
Twisting YES YES NO NO NONE
Coloring NO NO NO YES NO NONE
Pressing YES YES SOMETIMES NO NO NONE
Hammering YES YES YES NO NO NONE
SOLID LIQUID
HEATING
COOLING
MELTING
FREEZING

31.Mixture is a combination of two or more substance.
MIXTURE
Homogeneous Mixture Heterogeneous Mixture
Each of the combined/mixed substances
CANNOT be distinguished or identified
Each of the combined/mixed substances CAN
be easily distinguished or identified from one
another
Resulting mixture is same throughout Resulting mixture is different throughout
32.Solution is especial type of mixture that combines solids and liquid substances. It is
homogeneous in nature because the solid or soluble solute completely dissolves in liquid or
solvent.
SOLUBLE SOLUTE SOLVENT
The solid part that gets dissolved The liquid part that does the dissolving.
 When sugar is added to water and stirred, the solid sugar is the solute and it dissolves in water
as the solvent and forms a sugar solution.
33.Suspension is a heterogeneous mixture that combines insoluble solute that does not dissolve in
the solvent. The resulting mixture is cloudy.
INSOLUBLE SOLUTE SOLVENT
The solid part that does not dissolved The liquid part that does the dissolving
34.Water is considered as universal solvent.
 Water is a very good solvent as it can dissolve many substances such as sugar, salt, alcohol
and soluble food substances.
35. Liquid-Liquid mixture is a combination of two or more liquid substances. Some liquids when
mixed, give a uniform mixture, but others do not.
 Two liquids that do not mix form two layers.

QUARTER 2: LIVING THINGS AND THEIR ENVIRONMENT
CHAPTER 1: MAJOR ORGANS OF HUMANS
Bones Functions
Skull Protects the brain
Backbones Protects the spinal cord and supports our
whole body
Rib cage A protective cage around the heart and
lungs.
Pelvic bones Support our body when we sit.
36.The skeleton serves as the body’s framework. It helps support your body and helps you move.
 All the bones of our body and their connecting cartilages and ligaments make up the
skeletal system.
 A newborn baby have over 300 bones, a normal adult has 206 bones.
37.Long bones such as in your arms and legs are generally cylindrical in shape. They help you
make large movements such as running and walking.
38.Short bones such as those of the wrist and ankle, help you do all movements such as writing,
drawing and sewing.
39.Flat bones such as those of the ribs and shoulder blades are made up of spongy material
between two plates of hard bones.
40.Bones are linked together in the joints. A joint is a place where two bones come together. Joints
help move the bones easily.
41.In gliding joints the bone surfaces slide over one another. These joints are found between your
backbones or vertebrate.
42.Hinge joint move up and down or back and forth like the hinge of a door. The knees and elbows
have hinge joints.
43.Pivot joints are a special kind of hinge joint. These joints enable you to turn your head or twist
your forearm.
44.Ball-and-socket joints enable you to move your arms up, down and even turn around. The
shoulder and hip have ball-and-sockets joints.
45.Ligaments are tough, white cordlike bands that holds the bones together at the joints.
46.Cartilage is smooth, slippery tissue that coats the end of the bones
47.Tendons are tough cords which connect the muscles to the bones
48.Muscles give form or shape to your body. They also help the bones to move and protect delicate
organs. There are more than 600 muscles to move the parts of the skeleton.
 All the muscles of the body make up the muscular system.
 Muscles always work in pairs. They always pull. They become tight, short and big whey
they pull.

Three types of Muscles
Smooth muscles or
involuntary muscles
Controlled by the nervous
system
Muscles that cannot be
controlled like the walls of
stomach, esophagus,
diaphragm and walls of
blood vessels.
Cardiac muscles of
myocardium muscles
Controlled by the nervous
system
Muscular muscle of the
heart or the heart muscle.
It contracts to pump blood
out of the heart and then
relaxes as the heart refills
with returning blood.
Skeletal Muscles or
voluntary muscles
Controlled by the cerebral
motor cortex and
cerebellum
Muscles that are attached
to the bone and can
consciously controlled like
your arms, legs, face
muscles.
49.Injury- has harm or damage; an act or event that causes someone or something to no longer be
fully healthy or in good condition
50.Disease- an illness that affects a person, animal or plant; a condition that prevents the body or
mind from working normally.
51.The bones need calcium and the muscles need protein to become strong and healthy.
52.First aid treatment should be done when no doctor or immediate help is around.
 What can you do to take care of your bones and muscles?- Eat a balanced meal, maintain
good posture and get enough rest and exercise.
53.The handicapped are the physically challenged people such as the lame, blind, hunchback and
without arms or legs.
Common Bone Injuries
Fracture Is a break in the bone
Dislocation Occurs when a bone in the joint is displaced or has moved out of its
proper position
Common Muscle Injuries
Sprain An injury to a ligament caused by excessive stretching.
Cramps May develop when the muscles are tired and over stressed. It is a
strong muscle contraction that can be very painful lasting for a few
minutes
Common Bone Diseases
Fracture Is a break in the bone
Dislocation Occurs when a bone in the joint is displaced or has moved out of its
proper position
54.Stomach – is a large organ that is lined with layers of muscles.
55.Digestion- is a process by which food is broken down into nutrients to be absorbed by the blood
 Chew your food well to help in is digestion.
 Process of digestion is BOTH mechanical and chemical
 Mechanical Process- the tongue, lips and cheeks move the food between the teeth to break
it down into small pieces. The food in the stomach is squeezed, twisted and churned.
 Chemical Process- the mixing of food particles with saliva in the mouth that breaks down
starches into sugar and mixing gastric juices and enzymes in the stomach.
 The saliva contains an enzyme called ptyalin.

56.Ptyalin changes starches into sugar. Thus, rice and bread taste sweeter after you chew it for
sometime.
 The tongue helps you swallow the food. It pushes the food into the throat down into the
esophagus.
57.Through peristalsis (squeezing up and down movement), the food is pushed down into the
stomach.
 Food stays in the stomach for four hours until the food turns into a thick liquid.
 The food that has been moistened, chewed in the mouth and mixed with chemicals or
enzymes in the stomach goes into your small intestines.
58.Small intestines- is about 2.5 cm and 7m long coiled tube where food is finally digested and
absorbed.
 The walls of the small intestine are lined with villi a muscle that squeeze food and
continuously move it.
 It contains digestive juices and enzymes that help breaks the food into nutrients.
 The final digestion takes place in the small intestine. The nutrients are then absorbed by
the small intestines then go into your blood stream.
 Undigested food particles (like seeds, tough fruit pulp and not properly chewed meat) are
passed to the large intestine to be passed out of the body during defecation.
59.The liver, the largest gland of the body, secretes bile to digest fatty foods.
60.The pancreas, secretes pancreatic juice called insulin to digest starch, protein and sugar.
Common Ailments Related to Digestion
Ulcer/Hyperacidity Caused by not eating on time, too much intake of acidic drinks and
food
Diarrhea Frequent moving of the bowel with watery stool
Constipation Difficult elimination of dry and hard stool or feces
Appendicitis Inflammation of the appendix caused by irritation from undigested
food that may block it
Indigestion caused by too much or rapid eating or drinking
Gastroenteritis Caused by bacterial infection from taking contaminated food and
water
61.Kidneys are bean- shaped paired organs which are about four to five inches long and two to three
inches wide. They are the major organs of the urinary system.
 The right kidney is slightly lower due to the presence of liver on the right region of our body.
 The kidneys remove urea from the blood through tiny filtering units called nephrons.
 Two Major Functions of Kidneys
a. They remove liquid waste from the blood in the form of urine.
b. They keep a stable balance of salts and other substances in the blood and produce
a hormone that aids the formation of blood cells.
62.Heart (cardiac) is a hollow muscular organ located between lungs and it is protected by rib cage.
It is about the size of your fist and located in the middle of the chest cavity.
a. The pulse or heartbeat increases when one is engaged in a physical activity.
b. When muscle contraction of the heart increases, the heart works and can easily pumps blood
to distribute nutrients to the different parts of the body.
Common Heart Ailments
High- blood
pressure or
hypertension
It is characterized by a sudden rise of blood pressure.
Heart attack It occurs when blood clot or fat get lodged in blood vessels which
blocks the passage of blood to the heart
Rheumatic
fever
It is a complication of a throat infection
 Treatment for Lungs Ailments- Minimize your intake of salt (sodium) and fatty food, get enough
rest and sleep and exercise regularly.

63.The lungs filter the oxygen that enter our body because it contains a filtering structure that the
heart receives clean oxygen from the lungs.
a. The heart and lungs support each other to allow distribution of nutrients and oxygen to all parts
of the body and the removal of carbon dioxide as a waste product in the body.
Common Lungs Ailments
Asthma It is a condition where a person experiences difficulty in breathing
Rhinitis It is characterized by sneezing, nasal discharge and itchiness in the
nasal passage
Bronchitis It is characterized by persistent coughing and sometimes fever
Pneumonia It is an inflammation of the lungs. A person with pneumonia has a
cough that produces a yellow- green phlegm. Symptoms include
fever accompanied by chills, shortness of breath, sweating, spitting of
blood, and increased production of sputum. This is a serious disease
and the patient must consult a doctor immediately.
Cold It is marked by sneezing, runny nose, coughing, sore throat and
sometimes fever and headache.
Tuberculosis It is an acute or chronic infectious disease of the lungs. It is a highly
communicable disease.
Lung cancer It develops in response to prolonged exposure to irritants like tobacco
smoke.
64.Brain is a highly complex organ. It is found in the head and is protected by the skull, soft tissues
called meninges and a cushion of fluid. It weighs about 1.5 kilograms and contains billions of
neurons.
Functions of the Brain
a. It controls the voluntary activities of the body like thinking, solving problems, and
memorizing details and decision making.
b. It controls the muscles movement of our body like walking and writing.
c. It coordinated muscular actions.
d. It is responsible for man’s ability to learn habits and develop skills.
e. It helps maintain a person’s sense of balance.
f. It connects the brain to the spinal cord.
g. It controls the involuntary muscles of the body and coordinates functions like beating of
the heart and breathing.
 The main function of the brain is to process information it receives and to send instructions to
the different parts of the body.
DISEASES RELATED TO BRAIN
Migraine It is an intense pain in the head caused by stress, fatigue and sometimes
hunger.
Stroke It occurs when there is a blood clot or broken blood vessels going to the
brain. This can lead to temporary or permanent disability of the muscles to
move some parts of the body.
Epilepsy This is a disorder due to irregular electrical signals in the brain. This
results to unsteady or trembling of the body (seizures) and loss of
consciousness. This disorder is due to chemical poisoning and head
disturbances.
Parkinson’s disease It is characterized by shaking, trembling and rigidity of the muscles in the
face.

CHAPTER 2: ANIMALS
65.Adaptation is the structure or behavior that helps an organism survive in its environment.
 Body structures of animals help them to survive in their natural habitat.
 Animals have different body structures and coverings for survival.
 Animals move in different ways because they have different body structures adapted to
their habitat.
66.Aquatic animals are animals that lives underwater.
Characteristics of Aquatic Animals
a. They live in water.
b. Breathe with gills except whales and dolphins which breathe through lungs
c. Have fins and or paddles to swim, except crustaceans—shrimp, prawns, crabs, who walks
using their claws and feet.
d. Born alive or hatched from egg.
o Fish are covered with scales for protection from disease and from other animals that
live in water.
o Their scales are smooth and slimy, arranged overlapping from head to tail so as the
water slips smoothly as it moves forward.
o Fish have gills for breathing underwater and fins for swimming.
o Shrimps and lobster are covered with outside skeleton or exoskeleton while other
animals, clams and mussels are covered with shells.
67.Terrestrial animals are animals that live on land.
Characteristics of Terrestrial Animals
a. They live on land.
b. Have lungs to breathe.
c. Have legs to move around (walk, hop and jump) except snakes which uses their body to crawl.
d. Born alive or hatched from egg.
 Some animals use their paws, claws, mouthparts like beaks and teeth.
 Others use their sticky tongue, movable jaws and sucking tubes.
 Animals having the same mouth parts eat the same kind of food, e.g. animals with flat teeth
eat grass or plants, animals with sharp pointed teeth eat meat or other animals and there
are animals which have both of these kinds of teeth
68.Camouflage is an adaptation of animals to blend their color and shape with their environment as
a way to protect themselves against their enemies.
69.Mimicry is a behavior of animals wherein some animals imitate the shapes, smell, tastes, color or
even the sounds of other animals.
 Most insects secrete chemicals that they use to protect themselves like, squid, wasp, and
snake.
 Other animals protect their own kind. Monkeys, elephants, and penguins travel through the
jungle in family groups. They scatter themselves to look for food but they do not go far
from one another. When there is danger, they group together.
 Slow moving animals such as turtles, crabs, snails and oysters have protective shell
covers. When they sense danger they keep their bodies inside their shells.
 Animals get their food in different ways. They use different body parts to help them get their
food.
Type of Consumers
a. Herbivores—are plant eating animals. Animals that eat leaves or grass have flat wide teeth
for chewing and grinding.

b. Carnivores—are meat eating animals. They eat other animals using their sharp teeth and
claws. These animals usually have sharp- pointed teeth (canine) to tear meat into small
pieces. They also have sharp claws to catch their prey.
 Scavengers are carnivorous animals that feed on dead animals such as wolves, hyenas
and vultures.
c. Omnivores—eat both animals and plants. Omnivores have both sharp and flat teeth.
Group of Vertebrates
Body
Temperature
Body
Coverings
Respiratory
Organ
How they
are born
Mammals- dogs, cats, cows
whales, dolphins
Warm-
blooded
Hair or fur Lungs Born alive
Birds-needs incubation for the
egg to fertilized. The mother bird
sits on the eggs to keep them
warm while the embryo
develops.
Warm-
blooded
Feathers Lungs Hatched
from egg
Reptiles- do not need
incubation for the eggs to
fertilized, they have leathery
shells that prevent moisture from
escaping. Examples are turtle,
alligators and crocodiles
Cold-
blooded
Scales/shells Lungs Hatched
from egg
Amphibians- live in water as
babies and on land as adults.
Examples of frogs,
salamanders, toads
Cold-
blooded
Moist, slippery
skin
Gills when young,
lungs when adult
Hatched
from egg
Fish- the eggs are fertilized
externally by the male’s sperms.
Cold-
blooded
Scales/skin gills Hatched
from egg
GROUP OF MAMMALS
Placentals  The embryo receives nutrients
and oxygen from the mother’s
body through an organ called
placenta.
 The embryo is attached to the
placenta by a structure called
umbical cord.
 Examples of these mammals are
dogs, cats, dolphins, elephants.
Marsupials  They have pouches where their
young complete their
development.
 The young mammal is born while
still an embryo. The tiny baby
crawls into the mother’s pouch. In
the pouch, the baby feeds on the
mother’s milk.
 The baby stays in the pouch for
one or two months until its
development is complete.
 Kangaro is a marsupial.

Monotremes  Are egg- laying mammals. Their
eggs are soft- shelled and are
hatched after ten days.
 When the babies are born, they
are fed with milk.
 Milk comes from glands on the
mother’s belly. The glands have
no opening, so the babies suck
milk from the mother’s fur.
 Examples are duck- billed
platypus and spiny anteaters.

CHAPTER 3: PLANTS
70.Plants are multicellular living organisms such as trees, vines, ferns, moss and algae. They make
their own food and mostly stationary (cannot move).
 Plants living in different places are exposed to varied conditions however; their structures
are suited to particular needs. For example, forest plants tend to grow tall and sturdy.
 Shapes and sizes of the leaves are also important for survival. Plants like bananas produce
big, broad leaves to efficiently trap more energy.
 Plants with waxy leaves help to protect themselves from dehydration as a result of too
much exposure to the sunlight.
71.Angiosperms are plants that have flowers
72.Gymnosperms are plants that do not have flowers.
73.Conifers are gymnosperm plants that make their seeds inside their cones
What is common to all plants?
- All plants have leaves, roots, stem and flowers.
Do the plants have the same stem?
- No, plants have different stems. They differ in size.
74.Terrestrial plants are plants that grow on soil.
75.Aquatic plants are plants that have adapted to living within aquatic (water) environments. They
are also referred to as hydrophytes.
 Aquatic plants require special adaptations for living submerged in water or at the water’s
surface.
 Aquatic plants can only grow in water or in soil that is permanently saturated with water.
Characteristics of Aquatic Plants
a. A thin cuticle. Cuticles primarily discourage water loss; thus most hydrophytes have no need
for cuticles.
b. Stomata that are open most of time because water is abundant and therefore there is no need
for it to be retained in the plant. This means that guard cells of stomata are generally inactive.
c. An increased number of stomata, that can be on either side of leaves.
d. A less rigid structure water pressure supports them.
e. Flat leaves on surface plants for flotation.
f. Air sacs for flotation.
g. Smaller roots; water can diffuse directly into leaves.
h. Feathery roots; no need to support the plant.
i. Specialized roots able to take in oxygen.
Plants Specialized Structures
Marang, durian They have fruits with pungent odor
Kalumpang tree Noted for unpleasant smell of flowers yet attract flies to pollinate
Bird of paradise It has thick cuticle that filter strong light and guards against excessive
water loss
Talahib/cogon It has a sharp leaf that might cause you harm
Pineapple It has spines on their leaves

Cactus It has fleshy stems to conserve water for a long time
Citrus plants Their leaves and fruits have strong smelling oils that have unpleasant taste
Coconut It refers to as “Tree of Life” because all of its parts can be used for different
purposes.
Lipang aso Has tiny hairs on its stem.
Lotus Has flat, broad leaves.
Water Lily Have thick and buoyant leaves that help distribute weight over a arge area
thus helping them to float.
Water hyacinth Have long roots that helped them reach the soil under the water.

CHAPTER 4: HEREDITY AND VARIATION
76.Seed is a flowering plant’s unit of reproduction, capable of developing into another such plant.
Seed coat or testa- is the outer covering of the
seed. It protects the seed from injuries and from
drying up.
Cotyledon- is the off white and the biggest part
of the seed. It provides the young plant or seed
the food it needs for growth.
Embryo- is the young plant or immature plant
found inside the seed. It will soon develop into a
plant.
Plumule- it is considered to be the part that
develops as the first leaves of the new plant.
Hypocotyl- it is the off white part of the embryo
where the young root stem of the seed begins.
Radicle- it is the part of the seed that becomes
the primary root.
CLASSIFICATIONS OF PLANTS
MONOCOTYLEDONS or Monocots DICOTYLEDONS or Dicots
Seeds with one cotyledons Seeds with two cotyledons
Leaves are long, narrow and have parallel
veins
Leaves are broad and have netted veins
Stem of a monocot plant have spongy
material called pith which contains tiny
bundles of tubes which carry water and
minerals from the roots to the leaves.
Stem of a dicot plant have annual rings,
each ring shows one year of growth of the
three.
Flower parts are arranged in sets of threes.
The petals in each flower would have 3, 6
or multiples of 3.
Flower parts are arranged in sets of 4 or 5
petals in each flower or multiples of 4 or 5.

 Plants are called green
factories.
 Soil covers the big portion
of our earth surface.
Generally it gives
substance that terrestrial
plants need. This contains
nutrients, organic and
inorganic materials. Loam,
sand and clay are the
major types of soil. Each
type of soil sustains
different type of plants.
 Most green plants need light which can either be from the sun or artificial light.
 Sunlight helps the plant grow properly by using the light energy to change carbon dioxide
and water into sugar.
 Carbon dioxide from the air passes through the tiny openings on leaves called stomata.
 There are more stomata
under surface of a leaf
that on the upper
surface to prevent water
from evaporating too
quickly.
 Stomata closes at night,
providing another level
of water conservation.
77.Many plants also need
water and minerals from
the soil. Water carries the
nutrients from the soil and
transport to different parts
of the plant. These process
is called osmosis.
 Temperature influences
the lives of organisms. Maximum growth of plants is directly affected by temperature. Some
plants grow well when exposed to a very hot temperature while other grow best in cold
temperature.
78.Germination is the process in which the embryo or “baby plant” gets energy from the stored food
in the seed and starts to grow.
79.Metamorphosis is a biological process by which an animal physically develops after birth or
hatching. There are two types of metamorphosis: complete and incomplete or gradual.
 The term metamorphosis refers to the way insects develop, grow, and change form, usually
(but not always) accompanied by change of habitat or behavior.
 It is part of the life cycle of most insects.
80.Life cycle is a period involving one generation of an organism.
81.Complete metamorphosis refers to the four stages of life cycle of an insect such as housefly,
mosquito and butterfly. The four stages of complete metamorphosis are egg, larvae, pupa and
adult.

COMPLETE METAMORPHOSIS
a. Egg- a female insect lays egg.
b. Larvae- hatch from egg but do not
look adult insects. The stages of
growth in larvae are called instar.
 Larvae of butterfly is
caterpillar.
 Larvae of mosquito is
wiggler.
 Larvae of housefly is
maggot.
c. Pupa- larvae make cocoon around
themselves, and become busy
changing into their adult forms.
 Larvae of butterfly is
chrysalis.
 Pupa of mosquito is
tumbler.
d. Adult- after a period of time, larvae is nothing like it was, and exits the cocoon or larval body as
an adult. This life cycle starts over again.
Are butterflies important or harmful? Why?
- Butterflies are important because they contribute in pollination or the reproduction of flowers.
Are mosquitoes important or harmful? Why?
- Mosquitoes are harmful to humans because they carry dangerous diseases such as dengue
and malaria.
Are housefly important or harmful? Why?
- Housefly are harmful to our health because they carry hazardous germs in their legs and saliva
which contaminate the food
that we eat which result in
diarrhea or dysentery.
82.Incomplete metamorphosis
refers to the three stages of life
cycle of an insect such as
cockroach, grasshopper and
louse. The three stages of
incomplete metamorphosis are
egg, nymph and adult.
 About 12% of
insects go through
the three stages
of gradual metamorphosis or incomplete metamorphosis.
a. Egg- a female lays eggs. Sometimes the eggs are in group and protected by a covering or
case.
 Grasshopper eggs are laid as a cluster into the soil.
 Cockroach usually laid their eggs in dark places with plenty of cover, common
locations like cabinets and behind baseboards (where the wall meets the floors).
b. Nymph- the eggs hatch into nymphs. Nymphs look like small adults, but usually don’t
have wings. They eat, grow and change.

 Nymph molts their exoskeleton (hard protective covering) as they grow. As this
occurs, they gradually begin to look more and more like adult.
c. Adult-once the nymph has grown to an adult size, they stop molting (the process of
shedding or losing outer covering)
 Generally, adults are the only stage in an insect’s life when it has wings.
 Adults’ primary interest is mating.
FROG LIFE CYCLE
 A female frog lays its eggs among
water plants that thrive in water.
 A male frog drops its sperm on the
eggs.
 The eggs are not fertilized inside the
body of the female frog.
 Frog eggs hatched after 10 days.
 Tadpole’s hind legs enable them to
push itself to the surface of the water.
CHICKEN EGG INCUBATION
 The egg white is transparent while the egg yolk
is yellow.
 The yolk is where the life of birds originates. In
this yellow fluid parts of a chick will emerge. It is
found in the middle of the egg.
 The egg white serves as food provider to the
yolk as it continuous to develop from the date of its
birth (hatch) until the 21st
day or the hatching day.

HUMAN DEVELOPMENT STAGES
Infancy
 Infancy, typically the first year of life, is the first important stage of human development. Many
physical milestones occur during this stage as an infant gains control over its body. However,
infants must rely on others to meet most of their needs. They learn to trust other people as
needs are met. They need to feel this security in order to properly develop both physically and
emotionally.
 Like your puppy, an infant needs to be loved and nurtured. As you met the needs of your
puppy, he/she learned to trust and bond with you while he/she also developed physically.
 Childhood
 The next stage of human development is childhood, during which children start to explore and
develop a sense of independence. Eventually, children learn to make their own decisions and
they discover that their actions have consequences. As they learn and grow, they develop a
sense of self. Children need to be nurtured so that they develop self-confidence instead self-
esteem issues. Achieving a healthy level of self-confidence helps children stay motivated to
achieve. A child also needs guidance as they begin to test out new skills and gain confidence
in their decision-making.
 Do you remember when your puppy got big enough to start getting into things? You may have
had to make sure to put your shoes up or your dog would chew them as he/she was learning
what he/she should and shouldn't do.
 Adolescence
 During childhood, children begin to develop a sense of self and independence, and this
process continues in the next stage of human development. During adolescence, young men
and women are primarily concerned with finding their identity and expressing who they are in
the world. Puberty causes many physical changes to take place, and adolescents must adapt
to their changing bodies. All of these changes can make adolescence a confusing and
stressful period. As adolescents try to find their place, they may experiment with different roles
and make attempts to separate from authority figures. They are getting used to their bodies
and trying to find out where they belong. They may try out different hairstyles and hobbies in
an attempt to create an image of themselves they're comfortable with.
 Eventually, your puppy wasn't really a puppy anymore - he/she was growing into a dog. He/she
probably became a bit rebellious, too, and tested your authority from time to time. As you set
firm and consistent rules, your puppy became comfortable with his/her personality and place in
your home. Your overgrown puppy is very much like an adolescent.
 Adulthood
 Adulthood brings on even more new challenges and major decisions about school, career,
and home life. Early adulthood involves few physical changes, but it's a time of important
emotional development, as young adults decide where they want to live, who they want to live
with, and what type of work they want to do.

 Next comes middle adulthood, or middle age, when adults begin to deal with the physical
signs of age: wrinkles, gray hair, and maybe a few extra pounds. On top of physical changes,
most middle-aged adults also experience stress from dealing with older children and taking
care of aging parents. Most adults have the life experience and emotional stability to deal with
these challenges, but it's no wonder we use the term 'midlife crisis' for those who struggle with
this period of human development.
 Late adulthood, or old age, comes with its own unique set of physical and emotional
challenges related to aging. On the one hand, late adulthood offers senior discounts and often
comes with fewer responsibilities; but on the other hand, it also brings more health concerns.
As their bodies wear out, people face the reality that they will not be around forever. Older
adults are also at risk for loneliness and depression if they lose the activities and people that
provided them with meaning in their lives. It's important that family and social ties are
maintained during this period of life. Ultimately, adulthood stretches over many years of a
person's life, and it's the time in which we settle into our place in the world, raise our families,
and enjoy the benefits of belonging.

CHAPTER 5: ECOSYSTEMS
84.Interaction is a relationship that exists among organisms. It could be a positive or a negative
interaction.
 Living things constantly interact with their environment. Each kind of environment is made
up of biotic (living things) and abiotic (non- living things) components that interact and
depend on one another in different ways.
85.Ecology is a branch of Science that study the relationship and interactions of living things with
one another and with their environment.
 Ecology comes from the Greek word oikos which means “house” or “environment”
86.Ecologist is a person who studies the interactions among organisms and their environment.
 Ecologist classify the organization of the natural world into three main levels: (1)
populations; (2) communities; and (ecosystems)
87.Population is a group of the same kind (species) of living things that live in one area called
habitat.
88.Habitat is a place where plants and animals live.
89.Community is a group of animals and plant populations living together in the same environment.
90.Ecosystem consist of all living and non- living things in a given area that interact with one
another.
 It is the largest and the most complex level of organization with all the environmental
factors such as sunlight, climate, soil, water, air, space, nutrients, temperature and energy.
6 ELEMENTS OF ECOSYSTEM
Sun Provides the energy needed to make food out of abiotic or non- living
substances
Producers Consist mainly of green plants, such as grass and trees, which make food
by the process called photosynthesis.
Abiotic substances Are non- living things such as phosphorus, carbon dioxide, water and
other minerals which plants need in order to produce food and to grow.
Primary consumers Are the plant- eating animals or herbivores.
Secondary consumers Are animals that eat other animals or carnivores.
Decomposers Organisms that break down dead plants and animals into simple nutrients.
The nutrients go back into the soil and are used again by plants. Bacteria
and fungi are decomposers.

 There are interactions where both species benefit from the relationship and there are also
interactions where one species benefits but the other is neither affected nor harmed. These
interactions are beneficial/important for survival.
91.Symbiosis is the interaction between two different organisms living together.
 Host- usually the larger of the two organisms
 Symbiont- usually the smaller member

EXAMPLES OF MUTUALISTIC RELATIONSHIP
a. The bee and the
flower
 Bees fly from flower to flower gathering
nectar which they make into food
benefitting the bees.
 When the bees land on the flower, they
get some pollen on their hairy bodies, and
when the bees land on the next flower,
some of the pollen from the first one rubs
off, pollinating the plant. This benefits the
plants.
 In this mutualistic relationship, the bees
get to eat and the flowering plants get to
reproduce.
b. The spider crab
and the algae.
 Spider crabs live in shallow areas of the
ocean floor, and greenish- brown algae
lives on the crabs backs, making the
crabs blend in with their environment and
unnoticeable to predators.
 The algae gets a good place to live, and
the crab gets camouflage.
c. Crocodile and
plover bird
 The Egyptian bird sees the invitation, and
if one is nearby it will fly into the mouth of
the crocodile, eat the food stuck in its
teeth and fly away unharmed.
 The bird benefit by getting food, and the
crocodile benefits by having clean teeth.
d. Clownfish and sea
anemones
 A sea anemone makes an ideal home for a
clownfish. Its poisonous tentacles provide
protection from predators and a clownfish
makes its meals from the anemone's
leftovers.
 A clownfish can help an anemone catch its
prey by luring other fish toward over so that
the anemone can catch them.

EXAMPLES OF COMMENSAL RELATIONSHIP
Bird’s nest and a tree  Birds build nests on trees
 When a bird makes a nest in a tree,
the tree is not affected but the bird
benefits because it gets shelter and a
chance for prey
Shark and remora fish  The remora fish attaches to the belly of
the shark by a sucker disc in it’s mouth
 It travels everywhere the shark goes.
It also eats any leftover food from the
shark.
 The remora (sucker fish) benefits from
this relationship because it gets to eat
and transportation from the shark while
the shark is neither harmed nor
affected.
Orchid and a tree  The orchid grow onto tree branches
and gets more sunlight and it is easier
for the butterfly and bees to pollinate
them.
 In this kind of relationship, the orchid
benefits from the tree, but the tree is
neither affected nor harmed by the
orchid.

EXAMPLES OF PARASITIC RELATIONSHIP
Tapeworm and a human/animal  Tapeworms feed off food that
animal/human consumes and
gets a nice warm home.
 The animal/human often gets
sick and could die
Aphids and a Rose Plant  Aphids are lice that live on
plants and suck their juices
 The plant’s leaves fall and
eventually die.
Tick and dog  Ticks and fleas feed off the
blood of their host (dog) and
gets a nice warm home
 The host (dog) often gets sick
 The sizes of predator and prey population are related to each other.
 If the number of prey is large, the number of predators increases.
 As predators feed upon the prey, the number of prey begins to decrease.
 The number of predators decreases, since they have a smaller food supply.

EXAMPLE OF PREDATOR- PREY RELATIONSHIP (PREDATION)
Lion and zebra
EXAMPLE OF COMPETITION
Lion and cheetah
- Both species feed on similar prey
Crocodiles
- They compete with each other on
food, and living spaces.

QUARTER 3: Force and Motion
91. Energy is the ability to do work. Anything that moves is doing work and uses energy.
 Energy cannot be created nor destroyed.
 It can only be transformed from one form to another.
 Without energy, your heart cannot pump blood. You will not be able to move.
TYPES OF ENERGY
a. Potential energy- is energy at rest. It is the energy of matter due to its chemical composition,
condition, or position.
b. Kinetic energy- is energy in position. Any moving object is doing work and using energy. It will
continue moving and using energy until it is acted upon by an opposite force.
92. Force is either a push or a pull on an object.
 It can be due to gravity, magnetism, friction or anything that might cause an object to move.
 Force can change the shape, size or movement of an object.
 Pushing, pulling, pounding, compressing, bending, twisting, tearing, stretching or squeezing are some
ways of changing the shape of an object.
93. Friction is a force that slows down and stops moving objects.
 Friction is a force that slows down and stops moving objects.
 Friction occurs when an object slides across another object.
FACTORS AFFECTING FRICTION
 On a smooth surface, there are few bumps and hollows. There is less friction on a smooth surface.
The moving objects can move continuously with very little force counteracting them.
 On rough surface, there are many bumps and hollows. The rougher the surface, the greater friction is
produces; thus, the slower the objects move.
94. Magnets- have invincible magnetic field which attracts objects made of cobalt, iron and nickel.
 One end of a bar magnet is the North Pole and the opposite is the
South Pole.
 When the poles of the two magnets are put near each other, they
have a force that will either pull them together or push them apart.
 If the poles are different, then they will pull together, or attract
each other.
 If the poles are the same, then they will push apart, or repel each
other.
95. Magnetism is the push and pull of a magnet.

96. Heat is a form of energy. It is an energy produced by continuous motion of the molecules of matter. These
molecules are always in motion.
 The faster the molecules move, the more heat is produced.
 Heat is measured by calorie.
 Fire occurs when something burns. Fire is a chemical
reaction that produces heat and light.
97. Sun is the main source of heat.
98. Calorie is a measure of energy in food.
99. Thermal energy is a form of energy present in everybody
due to the motion of molecules.
100. Temperature indicates the amount of heat present in matter. It is in measured Celsius, Fahrenheit,
and Kelvin scales.
101. Thermometer is an instrument for measuring temperature, typically a narrow- sealed tube with
graduations and having at one a small bulb containing a silvery liquid called mercury.
 In the Celsius scale, boiling water has the temperature of 100 degrees Celsius (100ºC).
 In the Fahrenheit scale, the same boiling temperature has a temperature of 212 degrees Fahrenheit
(212ºF).
 These measurements are equal: 100ºC=212ºF for boiling water.
 In the Celsius scale, freezing water measures 0ºC.
 In the Fahrenheit scale, the same freezing water measures 32ºF.
 These measurement are equal: 0ºC=32ºF for freezing water.
 When matter absorbs heat, its temperature increases; when it loses heat, its temperature decreases.
HEAT TRANSFER

102. Sound travels in waves.
 Sound must travel through matter (solid, liquid, gas) to be heard.
 A sound is made when things vibrate. Sound travels by sending vibrations through matter.
 Sound travel FASTER in SOLIDS than in air (gas).
103. Echo- a sound or series of sounds caused by reflection of sound waves or bouncing back of sound waves.
105. Echolocation- location by sound. It is a means of locating an object based on an emitted sound and the
reflection back from it. It is used natural by some animals such as bats, whales and other marine animals..
 Is the used of high pitched sounds for navigating and locating prey. They are able to use sound to “see.”
THE PATH OF LIGHT
105. Light ALWAYS travel in a straight line when going through a single medium, any substance through which a light
wave can travel.
 In some media, such as air, light travels quickly.
 In other media, such as water and glass, light travels more slowly.
104. A laser (light amplication by stimulated emmision of radiation) is a narrow but powerful beam of light.
 It can travel long distances and still focus on a small area.
 We use laser light when we store information on a CD. It is also used to read bar codes in stores.
 Laser light has a great deal of heat energy. In industry, it is used to cut, drill and bond materials together. In
medicine, doctors use laser to treat certain problems with internal organs, the eye and the skin.
105. Optical fiber is a very thin glass or plastic that is bundled together in a coated, flexible tube.
 The tube can be twisted or bent without affecting the image that is sent.
 Optical fibers are made from transparent materials that transmit visible, ultraviolet and infrared light. The
information they carry quickly travels long distances.
 Optical fibers are used in communication, medicine and industry.

106. Reflection- the bouncing of light of an object.
107. Refraction- is the bending of the path of light when it moves from one kind of matter to another like from air to
water.
108. Absorption- the stopping of light when it hits a wall or other opaque object
109. Opaque- reflecting or absorbing all light; no image can be seen.
110. Translucent- allowing see light to pass through; blurry image can be seen.
111. Transparent- allows most light to pass through; clear image can be seen.
COLORS OF LIGHT
Refraction

QUARTER 4: EARTH AND SCIENCE
112. Soil is the foundation of life on earth. It is a system into which energy and matter from the sun, the
atmosphere, and living organisms penetrate and interact.
 It is a system because it is composed of many different parts.

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